It has long been recognized that the alpha-olefin content of various industrial hydrocarbon streams constitutes a valuable resource if the alpha-olefins can be suitably separated or recovered from the non-alpha-olefins with which they are associated. These streams may and often do contain close boiling isomers of alpha-olefins and internal olefins, along with paraffinic and/or other hydrocarbons such as naphthenes and aromatics.
In Boyer, U.S. Pat. No. 3,285,988, a process for recovering olefins from a mixed fluid stream is described. The process involves a pair of aluminum alkyl displacement reactions. In the first reaction the alpha-olefin-containing stream is reacted with trialkylaluminum in which at least one alkyl group contains from 2 to 4 carbon atoms, specifically triisobutylaluminum, at a temperature in the range of about 50.degree. to 300.degree. F. and for reaction times of at least 15 minutes, and preferably at least one-half hour. The resultant high molecular weight aluminum alkyl is recovered and subjected to a displacement reaction with a lower olefin, specifically isobutene, to release the alpha-olefins. It is indicated that in this reaction a catalyst, such as nickel or a nickel compound or cobalt, is usually used.
Feighner et al. U.S. Pat. No. 3,291,853 describes another process for accomplishing such separations. In this case the mixed stream is heated with a dialkylaluminum hydride at 80.degree. to 130.degree. C. so that the alpha-olefins react with the dialkylaluminum hydride to produce a reaction mass containing trialkylaluminum. The recovered trialkylaluminum is then heated to a temperature at which it decomposes to produce dialkylaluminum hydride and alpha-olefin.
A desirable contribution to the art would be novel, economically viable process technology whereby selective utilization of the alpha olefins present in a mixed hydrocarbon stream can be accomplished. This invention is deemed to constitute such a contribution.